This Independent Scientist Award (K02) application is designed to support career development in the studies of protein-assisted biomineralization: The role of post-translational modifications of extracellular matrix proteins (ECM) and its impact on mineral formation. This expertise will be applied to the applicant's funded R01 "Dentin Biomineralization" which involves the determination of the difference in phosphorylation patterns and sites of exon 5 of Dentin Matrix Protein 3 using mass spectrometry by analysing recombinantly produced phosphophoryn (PP) as well as purified PP from stably transfected non-mineralizing cells (NIH3T3) and cells that have the capability to mineralize (MC3T3-E1 and MDPC-23). In addition, we will assess how this post- translational modification impacts mineral formation. Career development skills will be applied to collaborative research with Co-PI and consultant. New career development activities in proteomics will include proteomics courses offered at the University of Pittsburgh, intensive workshops and hands on experiments in collaborator and core facility laboratories. This will involve sample preparation, running sample on MALDI-TOF/TOF-MS/MS and sample analysis. Career development in mineral characterization will include tutorials of the necessary equipment (x-ray diffraction, FTIR, SEM, TEM and EDAX), courses in Materials Sciences and Engineering focused on ceramics at Carnegie Mellon University, workshops, sample analysis in collaborator laboratory. The candidate will devote at least 75% of his time to research during the 5-year proposal duration and plans to attend a series of advanced courses, which include responsible conduct in science, career development and grant writing, bioethics, data management, writing and presentation skills. Support of this award will allow the applicant protected time to learn the fundamentals of mass spectrometry and mineral characterization as well as establish a strong research program focused on physiological/pathological biomineralization.